Belt pulley



June 6, 1939. E. K. ANDERSON 0 I BELT PULLEY Filed sept. 21, 1938 2Sheets-Sheet 1 X41117 r I Era ck Km Ami lNVENTOR ATTORNEY June 6, 1939.E. K. ANDERSON 2,161,270

' BELT PULLEY Filed Sept. 21, .1958 2 Sheets-Sheet 2 Er uck Kro'ws[\fldGhSc r1 INVENTOR J3; ATTORNEY.

Patented June 6, 193% UNITED STATES PATENT OFFICE BELT PULLEY ErichKrau's Anderson, Trenton, N. J. Application September 21, 1938, SerialNo. 230,914

' ol mfkol. 14-230.?)

This invention relates to improvements in the construction and operationof a belt and its pulleys to transmit power from one point to another ina mechanical apparatus.

5 i A belt is a flexible connector which'passes over a smooth-facedpulley wheel either flat or V- shaped and whose surface it grips byfriction alone. The belt does notprovide a drive of the same degree ofpositiveness as a chain and sprocket since the belt may at times slip onthe pulley wheel. This characteristic is often an advantage in favor ofthe belt, but more.often it is the reason for the useof a morepositivedrive although the belt might actuallyv be a better powertransmission medium if it were not for the inherent slippage between itand its pulleys.

It has been found of particularly practical value in powertransmissionto provide a pulley wheel and belt connector of a construction whichactually retains all of the desirable features of the flexible belt andsmooth face pulley wheel as well as the advantages associated with amore positive drive connection, e. g., chain and sprockets.

Therefore, it is the principal object of my invention to provide apulley wheel or its belt or .both with a friction surface having aplurality of suction spaces disposed in one of the contacting surfaceswhich in operation will have a tendency to grip the opposed surface andprevent all possible slippage between belt and pulley within certainlimits of tension equal, for example, to the breaking point of the belt.1

Another object of this invention is to provide the peripheral surface ofa pulley wheel with a i resilient ring having disposed in its outersurface a plurality of depressions or cup-shaped grooves for the purposeof creating a suction grip upon the contacting surface of the beltpassing over the ring.

Another object of the present invention is to provide opposite faces ofa resilient ring with vacuum spaces to cause the ring to adhere closelyappended claim, and illustratively exemplified in the accompanyingdrawings, in which V Fig. 1 is an elevational view of a pulley wheelwith resilient ring;

Fig. 2 is a front elevational view of a pulley wheel showing theperipheral surface construction of the resilient ring anda portion ofthewheel and rim in cross-section; t

Fig. 3 is a substantially transverse sectional view of a portion of thepulley wheel and.resilient ring;

Fig. 4 is a plan view of the resilient ring showing the surfaceconstruction; v

Fig; 5 is a sectional view of the pulley wheel and resilient ring havingsuction spaces on opposite faces thereof Y Fig. 6 is a sectional view ofa modified rim connection between the pulley wheel and resilient ring;

Fig. '7 is a substantially longitudinal sectional view of a V-shaped.pulley wheel rim and V- shaped belt.

Referring to the drawings and particularly to Figures 1 and 2, l0denotes a pulley wheel having the usual smooth surfaced rim ll. Mountedupon the rim II is a traction ring l2 made of rubber or any othersuitable resilient composite material. The ring I2 before being appliedto the rim I l is substantially smaller than the periphery of the rim sothat it is necessary to expand the ring and place it upon the rim whereit remains under tension to insure very close adhesion to the pulleywheel.

The resilient ring l2 on its outer peripheral surface is provided with aplurality of grooves I3, which may be of any shape or design but whichare limited in length so as not to project to the edges of the ring. InFig. 2, I have shown the grooves l3 of V-shape one following anotherand. having its arms projecting to points short of the side edges of thering. The belt i4 is shown embracing the grooved surface of the ring l2and extending beyond the opposite ends of the grooves l3.

In operation the stretch of the belt passing over the pulley from theloose to the tight side causes a tension in the belt and a frictionforce is developed which tends to squeeze the traction ring l2 and whichforces the air from the grooves l3. This condition upon flexing of thematerials creates a vacuum seal or grip between belt and ring andconsequently prevents creeping of the belt with respect to the pulleywheel.

This type of pulley with its resilient vacuum cupped surface eliminatesthe use of specially traction threaded belts and makes possible a moreaccurate control of belt driven machinery. In practice the present beltdrive has been found to be comparable with a chain drive givinginstantaneous pick up and stop which are particularly important safetyfeatures on all types of coasting equipment drives as well as on machinetools and lathes. No belt dressing as a traction dope is necessary withmy new belt drive, which meansa greater working life for the belt, infact the presentinvention in use prolongs not' only the life of the beltbecause of the uniform load distribution on the pulley surface, butlikewise reduces the wear of the pulley shaft bearings as against thevariable loads encountered with straight belt and pulley drives broughtabout by slippage between belt and pulley.

Referring now to a further embodiment of my invention illustrativelyexemplified in Figures 3 and 4, the pulley wheel I 0 is provided with atraction ring lZa adhering to the rim H, the ring I2a having its outerperipheral traction surface provided with successive oblong oroval-shaped depressions l5, each of whichunder slight compression of thering sets up a vacuum grip upon the under surface of thebelt- M. It isimportant to note that as in the otherembodiments the depressions do notextend at either end to the edge of the ring and the width of the beltis such as to insure complete coverage for the depressions.

In Fig. 5. the belt I4 is carried upon a resilient ring llb havinggrooves It in its outer surface and grooves I! in its inner surface, thelatter grooves setting up vacuum grips along the sur- Figure 6illustrates a further means of attach ing the ring I20 to a rim l8,which is provided with key slots It in its surface, the side wall ofeach slot being inclined away from its other side wall in the directionof movement of the pul ley. The inner periphery of the resilient ringl2c is provided with lugs 20 which fit into the slots l9 and bring abouta lock between rim and ring capable of absorbing the heavy shock loadsof large machinery in operation.

The present invention applied to V-belt drives is illustrated in Figure'7 in which 2i denotes the V-shape pulley rim and 22 the V-shape belt.The sides of the V-shape belt 22 are provided with vacuum cups ordepressions 23 which under tension in the groove of the pulley tend togrip the latter and prevent slippage.

Having described the various embodiments of my invention and the mannerin which the same operates, what I claim and desire to secure by LettersPatent is:

In combination, a pulley wheel having a smooth surface therein, aresilient ring disposed peripherally of the wheel and provided in itsouter surface with a series of depressions projecting to points short ofthe opposed sides of the ring and with further depressions in its innersurface, and a belt passing over said pulley in contact with the surfaceof the ring and completely covering the depressions in the outer surfacethereof, whereby the ring is compressed under the belt and the air isexhausted from both groups of depressions to set up a vacuum gripbetween the pulley and the ring on the one hand andthe ring and belt onthe other hand.

ERICH KRAUS ANDERSON.

